• 한국초등수학교육학회지
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• 제22권4호
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• pp.497-516
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• 2018

본 연구는 초등학교 5학년 학생들의 수학적 모델링 수업에서 모둠 구성 방법에 따라 수학적 모델링 과정 수행 능력과 수학적 추론 능력에 차이가 있는지 분석하였다. 이를 위하여 3가지 문제 상황으로 각각 8차시에 걸쳐 총 24차시의 수학적 모델링 수업을 설계 및 실시하였다. 그 결과 동질 모둠 보다는 이질 모둠에서 더 낳은 수학적 모델링 과정 수행 능력과 수학적 추론 능력을 보여 주었다. 본 연구 결과는 수학 수업에서 수학적 모델링을 적용할 때 모둠 구성의 관점에서 이질 모둠이 보다 효과적임을 시사한다.

• 한국학교수학회논문집
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• 제4권2호
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• pp.61-74
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• 2001

The purposes of this study are to develop the mathematical performance assessment tasks and to apply them to the middle school students. And I also intend to know the students' inclination and learning attitude to mathematics. In order to satisfy this study, I developed the performance assessment tasks and the standard program of marking about the mathematical function and statistics for the first grade students at middle school. After examining the students' basic investigation, their inclination and learning attitude to mathematics, I applied these developed tasks to them After that I put both classes and performance assessment into operation in all 15 periods. I set up two classes of the first grade students (49 students) at J middle school in Kongju, Chungcheongnam-do as a model group. The results of this study are as follows: First, owing to the developed performance assessment tasks of function and statistics, the teachers can operate the assessment system as a process of teaching and learning. Second, because of the application of mathematical performance assessment tasks, we can change the students' inclination and learning attitude to mathematics affirmatively. And by using these tasks, we can help the students to think mathematically. In this way, the students will be able to realize the real value of mathematics and have a growing interest in mathematics through all these meaningful processes. Judging from this study, we can elevate the students' abilities of problem solving and reasoning and improve teaching-learning method by applying the performance assessment tasks to them. Thanks to these tasks, the students will be changed affirmatively in their inclination and learning attitude to mathematics. I think that these tasks are very good assessment method which can call forth curiosity and interest. Besides, they can also help the students realize the real value of mathematics.

• Journal of international Conference on Electrical Machines and Systems
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• 제1권2호
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• pp.53-57
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• 2012

The mathematical model of a three-phase voltage source pulse-width modulation (PWM) DC/AC inverter is non-linear, and in view of the traditional linear control strategy it can not meet the requirements of designing a high-performance inverter. What's more, when the loads are not pure resistive loads, the inverter further requires that the controller possess high-performance. This paper proposes a nonlinear control strategy for the inverter called Passivity-based Control. We can alter the inverter model in three-phase abc coordinate to two-phase synchronous rotating dq coordinate for establishing the port-control Hamiltonian (PCH) model for this system. We can control the distribution of energy in the system to achieve the control aim. Simulation results show that the passivity-based control method can make this system possess a level of high-performance that is both robust and dynamic.

• East Asian mathematical journal
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• 제37권3호
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• pp.333-354
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• 2021

A support vector machine (SVM) is a state-of-the-art machine learning model rooted in structural risk minimization. SVM is underestimated with regards to its application to real world problems because of the difficulties associated with its use. We aim at showing that the performance of SVM highly depends on which kernel function to use. To achieve these, after providing a summary of support vector machines and kernel function, we constructed experiments with various benchmark datasets to compare the performance of various kernel functions. For evaluating the performance of SVM, the F1-score and its Standard Deviation with 10-cross validation was used. Furthermore, we used taylor diagrams to reveal the difference between kernels. Finally, we provided Python codes for all our experiments to enable re-implementation of the experiments.

• 소음진동
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• 제1권2호
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• pp.115-120
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• 1991

The impact hammer is extensively used in experimental modal analysis as a means to provide force over a broad range of frequencies. The hammer mass and the impact head are often changed to achieve a desired impact time duration with its corresponding input frequency spectrum, these mass changes affect the performance and sensitivity of the force transducer employed to measure the impact force. Both a mathematical model describing the effects of impact head and hammer mass on the performance of the force transducer and experimental verification of this model are presented here.

• 대한수학교육학회지:수학교육학연구
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• 제9권1호
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• pp.333-350
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• 1999

The purpose of this study is to define performance assessment of mathematics, to make a model of performance task of mathematics for the first grade middle school students in higher group, to examine validity and reliability of performance task and to investigate the effects on the students' achievement and attitude. It first defines performance assessment and exanmines its main features and scoring methods. Based on these, nine performance assessment tasks and scoring criteria were designed for the first grade middle school students in higher group. The validity of performance tasks were examined by experts. The loaming achievement and mathematical attitude test between two groups were performed as pre and post test. The thinking of students about performance assessment was investigated by attitude survey. The results of this study are as follows: First, the validity of the performance tasks is very high. Second, The control group. Forth, there is a difference in student's attitude about mathematics between scorer reliability was high due to the scorer training. Third, there is little difference in teaming achievement between experimental and experimental and control group in 5% meaningful levels. That is, student's of both groups attitude about mathematics comes negatives, but the width of change of negative attitude in experimental group is less than control group. In the trend of negative attitude of mathematics as grade comes higher, this results showed that performance assessment of mathematics had positive influence on attitude of mathematics. The result of survey about mathematical performance assessment experience showed that students have positive attitude to performance assessment and recognized effectiveness of the performance assessment of mathematics.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.937-941
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• 2004

Since semi-active suspension systems of automobile, of which suspension damper are controlled actively, exhibit high performance with light system weight, low cost and low energy consumption. From this view point, semi-active suspension systems are greatly expected to be in the mainstream of future controlled suspension systems. In this Paper, mathematical modeling and dynamic characteristics analysis of a reverse continuously variable damper and valve used for semi-active suspension systems are investigated. The mathematical model of piston with valve are proposed by IMAGINE/AMESim in the paper. To verify the mathematical model developed, the dynamic characteristics are simulated by IMAGINE/AMESim and are compared with experimental results. It was confirmed that the developed models represent well the actual system and can be used for control system design.

• 공학교육연구
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• 제14권6호
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• pp.67-72
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• 2011

This method is a new experimental model for a mathematical education in Engineering students. We compare two different classes; one was recorded the lecture with scenario and the other was not. Also we set up the detailed structures in every lecture for mathematical modeling and solving parts. The purpose for a new model is 1) to improve the students's ability to solve the mathematical problem, 2) how to approach to getting a solution for each problem by system and 3) to provide the lectures anytime to students who want to study more mathematics.

• 대한수학회지
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• 제59권2호
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• pp.217-233
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• 2022

Although machine learning shows state-of-the-art performance in a variety of fields, it is short a theoretical understanding of how machine learning works. Recently, theoretical approaches are actively being studied, and there are results for one of them, margin and its distribution. In this paper, especially we focused on the role of margin in the perturbations of inputs and parameters. We show a generalization bound for two cases, a linear model for binary classification and neural networks for multi-classification, when the inputs have normal distributed random noises. The additional generalization term caused by random noises is related to margin and exponentially inversely proportional to the noise level for binary classification. And in neural networks, the additional generalization term depends on (input dimension) × (norms of input and weights). For these results, we used the PAC-Bayesian framework. This paper is considering random noises and margin together, and it will be helpful to a better understanding of model sensitivity and the construction of robust generalization.

• Journal of Biosystems Engineering
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• 제13권4호
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• pp.30-37
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• 1988

A mathematical model was developed and programmed for computer simulation of a prototype hot water boiler system with rice hull furnace to predict the temperature distributions in the rice hull furnace and water tank, mass flow rate of hot water and thermal efficiency of the system under various operation and design conditions. The effects of feed rate of rice hull, thickness of the furnace wall, the type of heat exchanger, diameter of the water circulation pipe, etc, on the performance of the system can be evaluated with this model. The validity and simulation results of this model will be published in the next paper.